This invention relates to a guide system mounted on an overhead door, specifically an overhead door which is guided along a predetermined path by a pair of tracks, and is able to be disengaged from one or both tracks when acted upon by an outside force. Once the outside force is removed, the door is able to automatically reset itself into the tracks. This ability to be disengaged will greatly reduce the possibility of damage to the overhead door other components of the installation.
During the course of daily activity around a loading dock or other industrial location, an overhead door may be impacted by a truck, forklift, or other forceful means. If the door is not able to move with this impact, damage to the door, tracks, or other objects will result. Various means have been used to allow a door to move out of its tracks to avoid such damage.
For example, U.S. Pat. No. 5,535,805 discloses an overhead door system in which a spring loaded pin retracts into a housing when the door is impacted. The pin is forced into its housing by means of a track whose cross section employs a slanted ramp. There are several disadvantages in this system. One disadvantage is that it is necessary to use a track with a ramped cross section. This limits the choice of door tracks, and any deformity in the ramped cross section will hinder proper operation. Another disadvantage is that the pin and its associated components must be kept lubricated and free of corrosion for it to work properly. Yet another disadvantage is that this system is limited to use on doors which are no wider than 16 feet. If a wider door is impacted, it is likely that the door will buckle before there is adequate force applied at the ends of the door to move the spring loaded pin up the ramp, unless the door is heavily reinforced.
A. Objects of the Invention
One object of the present invention is to provide a means to protect doors and their associated components from extensive damage resulting from an impact by an outside force.
Another object of the present invention is to provide a means for the protection device to automatically reset once the outside force is removed.
Another object of the present invention is to provide a means to protect very wide doors.
Another object of the present invention is to provide means to install this system on existing doors with a variety of track styles.
B. Summary
The present invention is a device which is designed to allow a door to give way when impacted by an outside force such as a forklift, reducing damage. The present invention requires less force to be activated, which allows its use on wider doors than were previously possible. The present invention is also able to reset itself, depending upon how much distance was traveled during the impact. The present invention requires less maintenance than other devices currently in use.